Differences Between Graphene and Graphite

Graphene is simply one atomic layer of graphite - a layer of sp2 bonded carbon atoms arranged in a hexagonal or honeycomb lattice. Graphite is a commonly found mineral and is composed of many layers of graphene. The structural make-up of both graphene and graphite, and their fabrication methods are slightly different. This article highlights the difference between these two materials.

Graphite Mineral

Graphite is one of the three naturally occurring allotropes of carbon and occurs naturally in metamorphic rock in different parts of the globe, including South America, Asia and some parts of North America. This mineral is formed as a result of the reduction of sedimentary carbon compounds during metamorphism.

Graphene

The chemical bonds in graphite are similar in strength to those found in diamond. However, the lattice structure of the carbon atoms contributes to the difference in hardness of these two compounds; graphite contains two dimensional lattice bonds, while diamond contains three dimensional lattice bonds. The carbon atoms within each layer of graphite contain weaker intermolecular bonds. This allows the layers to slide across each other, making graphite a soft and malleable material.

Various studies have demonstrated that graphite is an excellent mineral with several unique properties. It conducts heat and electricity and retains the highest natural strength and stiffness even in temperatures exceeding 3600°C. This material is self-lubricating and is also resistant to chemicals.

Although there are different forms of carbon, graphite is highly stable under standard conditions. Depending upon its form, graphite is utilized for a wide range of applications.

Graphene: Wonder Material

Graphene has unique properties that exceed those of graphite. Although graphite is often used to reinforce steel, it cannot be utilized as a structural material on its own because of its sheer planes. In contrast, graphene is the strongest material ever found; it is more than 40 times stronger than diamond and more than 300 times stronger than A36 structural steel.

Since graphite has a planar structure, its electronic, acoustic, and thermal properties are highly anisotropic. This means, phonons pass much more easily along the planes than they do when trying to pass via the planes. However, graphene has very high electron mobility and, like graphite, is a good electrical conductor, due to the occurrence of a free pi (p) electron for each carbon atom.

However, graphene has much higher electrical conductivity than graphite, due to the occurrence of quasiparticles, which are electrons that function as if they have no mass and can travel long distances without scattering. In order to fully realize this high level of electrical conductivity, doping needs to be carried out to overcome the zero density of states which can be visualized at the Dirac points of graphene.

Creation or Isolation of Graphene

Scientists use a number of techniques to produce graphene. Mechanical exfoliation, also known as the adhesive tape technique, is one effective way of creating single layer and few layer graphene. However, various research institutions worldwide are trying to find the most efficient way of creating high-quality graphene cost effectively on a large scale.

Chemical vapour deposition (CVD) is the most suitable technique for producing monolayer or few layer graphene. This technique is capable of extracting carbon atoms from a carbon rich source by reduction. However, a major drawback in this technique is the difficulty in locating a suitable substrate to grow graphene layers on as well as the complexity in removing the graphene layers from the substrate without altering or damaging the graphene’s atomic structure.

Conclusion

Other techniques for growing graphene are sonication, thermo-engineering, carbon dioxide reduction, cutting open carbon nanotubes, and graphite oxide reduction. This latter technique of using heat to reduce graphite oxide to graphene has recently attracted significant attention owing to reduced cost of production. Nonetheless, the quality of graphene produced presently does not meet the theoretical potential of the material and will take some more time to perfect.

About Graphenea

Graphenea is a leading graphene producer for industrial and research needs. Graphenea has developed a leading synthesis and transfer process to obtain high uniformity monolayer graphene films on any substrate.

This information has been sourced, reviewed and adapted from materials provided by Graphenea.

For more information on this source, please visit Graphenea.

Comments

  1. ahmad sh ahmad sh Iran says:

    hi
    can u explain why the graphene is so hard hile the graphite is so soft?
    tnx

    • Noddy Wellington Noddy Wellington Australia says:

      If graghene is 300 times stronger than diamond then I would say that it has perhaps a 3 dimensional lattice.  Plus it has an free p electron.
      I don't know much about this and I have only come to this conclusion by reading this material.  However I think its terrible that those that know have ignored you for several months.

    • DJ Nicke DJ Nicke Australia says:

      Graphite is layers and layers of graphene piled up on top of each other with weak molecular bonds between the layers - therefore the layers shift and slide over each other, and the overall material appears soft at human scale.

      However, individual layers of graphene are only one atom thick. They are invisible to the naked eye, yet they do not allow ANY element to pass through - not even Helium - it's a transparent yet impermeable membrane.

      The honeycomb structure of the flat sheet is what gives it the strength 40 times stronger than diamond and 300 times stronger than steel. But even so, a sheet one atom thick isn't going to be very strong.

  2. Noddy Wellington Noddy Wellington Australia says:

    If graghene is 300 times stronger than diamond then I would say that it has perhaps a 3 dimensional lattice.  Plus it has an free p electron.
    I don't know much about this and I have only come to this conclusion by reading this material.  However I think its terrible that those that know have ignored you for several months.

    • DJ Nicke DJ Nicke Australia says:

      Graphene is 40 times stronger than diamond, but 300 times stronger than steel.

      It is a 2d structure - perfectly flat sheets of carbon atoms arranged in a hexagonal honeycomb pattern.

  3. Hemanth Kuamr Hemanth Kuamr India says:

    may i know the thermal coefficient of expatiation of graphene...thank You

  4. Vincent Wang Vincent Wang Canada says:

    Diamond is not strong at all, certainly not stronger than diamond, although it can't be 30 times harder than diamond, diamond is extremely hard, but not strong at all.

    • DJ Nicke DJ Nicke Australia says:

      Strength refers to the maximum stress before failure occurs.

      The molecular bonds of diamond are stable, giving them strength 7.5 times greater than steel.

      That means a rod of diamond could carry a load (push, pull) 7.5 times greater than a rod steel with the same dimensions.

      Graphene is 40 stronger than diamond and 300 times stronger than steel - meaning a beam constructed of graphene would hold 300 times the load of a steel beam with the same dimensions.

  5. arvind1997 ravi arvind1997 ravi India says:

    what is the form of carbon ? whether it is in powdery form or sheets ?how can we say that graphene powder is stronger although it is in scattered and powdered form?

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of AZoNano.com.

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